2014 — 2023
4.0L V8 (M178) - GT
Petrol
Test drive task: During a cold start, listen closely for a slight rattle from the front of the engine. | Detail: It is worth noting that the M178 engine can occasionally present with issues related to the hydraulic valve lifters; while not universal, it is a point to be mindful of during your inspection.
Test drive task: Perform several low-speed maneuvers in a quiet car park with the steering at full lock. | Detail: In cars of this nature, you may notice 'tyre scrub' or skipping due to the aggressive front suspension geometry; it is helpful to ensure this is purely a characteristic of the setup rather than worn suspension bushings.
Test drive task: Check the infotainment screen and climate control interface for any flickering or non-responsive menus. | Detail: As these vehicles feature complex electronic architecture, it is common to consider that minor software glitches or connectivity issues can arise as the car ages.
Test drive task: Inspect the underside and wheel wells for any signs of weeping around the adaptive dampers. | Detail: It is a good idea to confirm the electronic damping system is functioning correctly, as leaks can occasionally occur in higher-mileage examples.
Consider a major service including spark plugs and transmission fluid flush.
Likely time to assess the condition of the engine mounts and secondary cooling system components.
A proactive interval to inspect timing chain tensioners and auxiliary drive belt systems.
Ensure the 7-speed DCT transmission fluid has been changed according to the schedule to maintain smooth engagement.
Regularly monitor engine oil levels, as these performance V8s can consume small amounts of oil during spirited driving.
Keep up with the 'Service A' and 'Service B' rotations strictly using Mercedes-approved lubricants.
Check tyre tread wear patterns frequently to ensure the wheel alignment remains within factory specifications.
Keep the drainage channels clear to prevent moisture ingress into the electronic control modules located in the cabin and trunk.
Estimated repair costs if issues arise
If the electronic suspension components require replacement in the future, it is a significant job that involves replacing the active strut units. Depending on the car's history, you might eventually need to budget for this.
If your chosen vehicle is equipped with the optional carbon ceramic discs, please be aware that replacement rotors are a premium item. If this component needs attention in the future, the estimated cost in NZ is substantial.
The dual-clutch transmission is incredibly responsive, but like all high-performance gearboxes, it may eventually require a refresh of the clutch packs if you notice any slipping or hesitant gear changes. It is wise to set aside funds for this eventuality.
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Disclaimer: This report is generated with the assistance of AI analysis based on verified automotive data. While we strive for 100% accuracy, enthusiasts should always conduct physical inspections and consult service records. View Full Disclaimer